The following relates generally to transmitting information between a source and a receiver in a wireless communication system, and more particularly to designs for channel estimation using linear phase estimation.
Orthogonal frequency-division multiplexing (OFDM) is a digital multi-carrier modulation scheme which uses a large number of closely-spaced subcarriers made up of an orthogonal set of data symbols to transmit information. These subcarriers typically overlap in frequency, but may be separated at receivers using algorithms such as a Fast Fourier Transform. Each subcarrier is typically modulated with a conventional modulation scheme, such as quadrature amplitude modulation or amplitude phase and shift keying, in order to maintain a data rate similar to a single-carrier modulation scheme. In orthogonal frequency division multiple access (OFDMA) systems multiple users are allocated different groups of OFDM subcarriers, which are sometime referred to herein as subchannels or channels. The reuse of subcarriers between neighboring cells as well as the spacing between subcarriers from all of the cells results in co-channel interference.
Typical techniques to estimate the channel response between the source and the receiver in OFDM systems use a pilot signal sent by source to a receiver. Conventionally, channel estimation techniques use complex linear operations such as maximum likelihood (ML) channel estimation, minimum mean squared error (MMSE) channel estimation, and weighted average channel estimation. Each of these approaches have high complexity and may require prior knowledge of channel statistics.